LU87167A1 - PREPARATION OF SUPER-CONDUCTIVE OXIDE-METAL OXIDES AND COMPOSITES - Google Patents

Abstract

A superconducting oxide-metal composite, comprising a superconducting oxide phase and a noble metal phase to provide said composite with improved mechanical properties. Said superconducting oxide phase being present almost continuously throughout the composite and said noble metal is precipitated in the oxide phase as finely divided substantially pure metal phase and is intimately mixed in the composite for acting as a skeleton in the composite to improve the ductility and strength of said composite.

Description

L-3215

F Ql Λ ΡΓΤ7 GRAND-DUCHY OF LUXEMBOURG

Patent N ° JD ....... / ____________ I_______9 "* .. ....

Minister of 1.8 ...... ffi§ £ S ...... 1.9.88 _________. of Economy and Classes fl / ioveEBA ΕΡΟΌΕΒ J DG 1 _ ...., 3¾¾ Intellectual Property Service: tuelle peçU.

....... ire 1Vre '^ ........................... ~~ LUXEMBOURG 0 2 -06 "1S88

Patent application d91nvÆitio.nlBaZ

---------------------------------------------------------- ---------------------------------------------------------- -------------------- (1) I. Request

Massachusetts Institute of Technology, 77 Massachusetts Ave- (2) nude, Cambridge / MA 02139, USA, represented by Jean_

Waxweiler, 55 rue des Bruyères, Howald, acting as agent · .......................... '........ .. .........

---------------------------------------------------------- ---------------------------------------------------------- ---------------------------------------------------------- -------------- 1, 3) deposit) this eighteenth of March one thousand nine hundred and eighty-eight _________ (4) at i5./..9 .9.— hours, at Ministry of the Economy and the Middle Classes, in Luxembourg: 1. this request for obtaining a patent of invention concerning: .Brépar.atiou „jd .. '.. Qxydes ..... je .t_de. ™ jc.Qmp.o..s: ites .... Q.xy.de-mé ±. „al„ ._ sup.r.ac.Qn- (5) ducteurs___________________________________________________________________________________________________________________________________________________________________________________________ 2. description in language - French ---------------------- of the invention in triplicate; 3 ...................... / .......................... .................... drawing boards, in triplicate; 4. the receipt of the taxes paid to the Luxembourg Registration Office, on 18.03.1988 __________________________.

5. the delegation of power, dated______________________________________ on_________________________________________________; 6. the successor document (authorization); declare (s) assuming responsibility for this declaration, that the inventor (s) is (are): (6)

Gregory ...... J .., ........ Yurek, ......... 5.4 ...... Hundreds Road, Wellesley. MA 02181, USA_______

John ..... B ....... VanderSande, 5 High Road, Newbury, MA 01951, USA __________ · claims (s) for the above patent application the priority of one (s) application (s) (7) ................... patent ........................... .................................................. ................................. filed in (8) ...... E-. -U -.- Ä ·· ................... · __________________________________________________________________________ on (9) 2.7 ....... Tue..S ..... ..1.98.7 <=> + · ....... 1Q ....... June 1987 ...................... .................................................. .................................................. ...................................

under N ° (10) ...... 031,407 ..... and 061,233, resp ._____________________________________________________________________________________________________________________ in the name of (U) Gregory ...... J. Yurek and John B. Vander Sande ........................................... ...............

elect (elect) domicile for him / her and, if designated, for his / her representative, in Luxembourg_____________________________________________________ .5.5 ...... rue ..... des ...... Bruyères .., .... ... Howald__________________________________________________________________________________________________________________________________________________________________________________________ (12) seeks) the grant of a patent for the invention for the subject described and represented in the abovementioned appendices, with deferment of this grant to. ! ../) .............................. (Z..1 .......... .................................................. .................................................. ....................................... months. (13)

Lodfoesaofe / agent: —............; ........... J .................... .................................................. .................................................. ............................... (14) Π. Deposit Minutes

The above application for a patent for invention has been filed with the Ministry of the Economy and the Middle Classes, Intellectual Property Service in Luxembourg, on: 18.03.1988 / "··. \\ Pr. The Minister of Economy and the Middle Classes, (g | §Â \\\ / _ "j The head of the intellectual property department, A 68007. / EXPLANATIONS RELATING TO THE FORMULÂIli'SErÔrtlÎ" ^ Ί η -, (X) if there is takes place "Request for certificate of addition to the principle principle * to the main patent application No ............ of ...........” - (2) enter the surname, first name, profession, 'f \\ address of the applicant, when the applicant is an individual or company name, legal form, address of the head office, when the applicant is a legal person - (3) enter w >> Ο V, the surname, first name, address of the authorized representative, industrial property attorney, with special powers, if applicable: "represented by ............ acting as agent ”- (4) date of deposit in full - (5) titr e of the invention - (6) enter the names, first names, addresses of the inventors or the indication "(see) separate designation (will follow)", when the description is made or will be made in a separate document, or the indication "do not mention", when the inventor signs or signs a non-mention document to be attached to a designation

CLAIM OF PRIORITY

Filing of the patent application in the United States of America of March 27, 1987 UNDER number 031,407 and of June 10, 1987 under number 061,233

MEMORANDUM OF SCRIPTURE FILED IN SUPPORT OF A PATENT INVENTION APPLICATION IN THE GRAND DUCHY OF LUXEMBOURG

pqr; Massachusetts Institute of Technology

77 Massachusetts Avenue Cambridge, MA 02139 USA

for; Preparation of oxides and oxide-metal superconductive composites.

I

►

PREPARATION OF OXIDES

AND SUPERCONDUCTING OXIDE-METAL COMPOSITES

5 This patent application is a partial continuation of U.S. Patent Application No. 031,407 filed March 27, 1987, entitled "Preparation of Superconductive Oxides and Oxide-Metal Composites".

The present invention relates to superconductive materials.

Superconductors are materials with practically zero resistance to the flow of electrons below a certain critical temperature, T. It is known that certain metal oxides, for example La. Ba CuO,, La_ Sr Cu,, Ba_YCu_0_ ... pre-

2-x X 4-y 2-X x 4-y 2 3 9-Y

feel a superconductivity. It has also been discovered by the applicant that a europium-barium-copper oxide, in which the europium, barium and copper are in the ratio 1-2-3, that is to say in the 20 EuBagCUgO ^ report, exhibits superconductivity with a transition temperature of about 85 * K. It is desirable to provide such oxides in forms, for example wires or thin films, which allow the practical use of their superconductive property.

In general, the invention describes by one of its aspects the combination of metallic elements of the desired superconductive oxide to form an alloy, and the alloy oxidation to form a superconductive oxide. The alloy can be made, for example, into a wire, a ribbon, a sheet, a rod or a ring. The solid alloys used to manufacture these articles can be prepared from the liquid state by rapid or conventional solidification treatment techniques to produce, for example, ribbons, + 2 powders, scales, ingots, sheets or castings. Rapid solidification treatment techniques include melt spinning to produce ribbons and atomization in an inert gas to produce powders or spray deposits. Conventional solidification processing techniques include shell casting, ingot casting, pressure casting and centrifugal casting. The thermomechanical transformation of the 10 solid alloys can be used to transform them into the final, usable forms, before oxidizing the alloys to the superconductive oxide. Thermomechanical processing techniques include wire drawing, extrusion, co-extrusion, hot iso-static compression and rolling.

The alloy can also be provided in the form of a relatively thick coating, for example on a tube, wire, rod or a shaped article such as a ring. Relatively thick coatings of the alloys can be produced by co-extruding the alloy powder with a billet of a metal or metal alloy of the substrate to form wires, rods or tubes. Alloy coatings can also be produced by plasma spraying or by sputtering the constituents of the alloy onto a metal or metallic substrate alloy which can be in many useful forms, for example a tube brought under the shape of a ring. In addition, alloy coatings can be produced by hot immersion of the metal or the substrate metal alloy, for example in the form of wire, in the liquid alloy.

The alloy before oxidation can also be in the form of a thin film on a metallic, insulating or semiconductor substrate, for example as used i.

3 in a Josephson junction device of an integrated circuit. Thin films of the alloy can be produced by chemical vapor deposition, vacuum evaporation, sputtering, epita-5 xie of molecular beams, mixing of ion beams and ion implantation.

In another of its aspects, the invention describes an oxide-superconductive metal composite in which a noble metal phase (noble in the sense that its oxide 10 is thermodynamically unstable under the reaction conditions used with respect to the superconductive oxide which form) is intimately mixed with a superconductive oxide phase to achieve the desired mechanical properties. In preferred embodiments, the noble metal is initially present as an addition element with the metallic elements of the oxide; the alloy is then oxidized under conditions which transform metallic elements of the oxide into the superconductive oxide without oxidizing the noble metal. The latter precipitates in the form of a finely divided, practically pure metallic phase (rather than in the form of a second oxide phase), which is intimately mixed with the superconductive oxide in the final composite, the oxide phase being continuous (or almost 25 continuous) throughout the volume of the composite. The noble metal can be a metallic element different from the metallic elements of the oxide, for example Au, Pt, Pd or Ag, but it can also be a (stoichiometric) excess of one of the metallic elements of the oxide, for example example 30 Cu. Superconductive oxide-metal composites have improved mechanical properties (strength, ductility, etc.) because these properties are dominated by the metallic phase rather than the brittle oxide phase.

Examples of suitable oxides are described therein, in the following references incorporated in the present specification by way of reference and forming part of this patent application: Chu et al. (1987) Phys. Rev. Lett. £ 4 (4) 405-07; Cava et al (1987) Phys. Rev. Lett.

5 £ 4 (4) 408-10; Wu et al (1987) "Superconductivity at 93K in a New Mixed Phase Y-Ba-Cu-0 Compound System at Ambient Pressure“ (presented in the publication, annexed copy) i Hor et al. (1987) “High Pressure Study of the New Y-Ba-Cu-0 superconducting Compound System "(presented 10 at publication, copy attached); Tarascon et al.

(1987) “Superconductivity at 90K in a Multi-Phase Oxide of Y-Ba-Cu" (presented in the publication, annexed copy); Gleick, “Superconductivity: A New Era of Discovery for Electricity“, NY Times, 10 March 1987 ; and Tarascon et al. (1987) Science 235: 1373-76. They include, for example, oxides of La, Ba and Cu; La, Sr and Cu; Lu, Ba and Cu; Lu, Sr and Cu; and Y , Ba and Cu. The invention is obviously applicable to any superconductive oxide. It has been found that a europium-ba-20 ryum-copper oxide is particularly preferred, namely EuBagCu ^^. This invention covers other compounds, including europium.

Other characteristics and advantages of the invention will appear on reading the following description of these preferred embodiments, and of the claims.

The preferred embodiments of the invention are described on the basis of the following examples. 1 2 3 4 5 6 i EXAMPLE_1 2

A superconductive oxide of La, Ba and 3 is prepared

Cu in the following manner.

4

Pure La, Ba and Cu (73.3 t by weight of 5

La, 8.1 Z by weight of Ba and 18.6 1 by weight of Cu) are 6 melted under vacuum in an induction melting furnace 5 in a spinning apparatus in the molten state. The liquid alloy is heated to about 800 ° C and then spun in the molten state to produce a ribbon of the alloy.

The alloy ribbon is oxidized by heating to a constant temperature of 45 ° C. in a stream of pure gaseous oxygen until it is completely oxidized. The temperature is then raised to 1000 ° C. and maintained at this value until the weight of the sample is approximately constant and the oxide is homogeneous as regards the composition. The temperature is then lowered to 490 ° C and maintained at this value for about 18 hours. The temperature is then lowered to room temperature.

i 15 EXAMPLE 2

A superconductive oxide-metal composite is prepared in which the oxide phase is an oxide of La, Ba and Cu, and the metallic phase is a noble metal such as Ag, by following the procedure described in Example 20 1, except that the metallic Ag is melted with La, Ba and

Cu to form the alloy, that the initial oxidation stage is at 400 * C and that the maximum oxidation temperature is lower than the melting point of the metallic Ag (960 * 0. During the oxidation, Ag is not oxy-25 but rather precipitates in the form of a separate phase of practically pure Ag. The metallic phase, being intimately mixed with the oxide phase, behaves like a "skeleton" in the composite, which leads to improved ductility and strength.

30 EXAMPLE_1

A superconductive oxide-metal composite is prepared as in Example 2. except that the noble metal is excess Cu, rather than metallic Ag. During the oxidation, the temperature, the partial pressure of oxygen and the reaction time are chosen to achieve the stoichiometry of the oxide required for the superconductivity without oxidizing the excess metallic Cu to CUgO and / or to CuO. Thus, the final composite consists of a superconductive La-Ba-Cu oxide phase and a practically pure Cu metal phase.

EXAMPLE 4

The alloy ribbon prepared in Examples 1, 10 2 or 3 can be brought for example in the form of a ring or a coil before oxidation, then oxidized to give an oxide or an oxide-superconductive metal composite. of the desired shape.

15 EXAMPLE 5

An oxide or oxide-metal superconductive composite is prepared as in Examples 1, 2 or 3, but in the form of a wire, initially supplying the alloy in the form of a compact isostatic-hot compressed tablet of a rapidly solidified powder, a quickly solidified ground tape or a cast billet, then transforming it into a wire by wire drawing. The wire is then shaped by winding it around a metallic core and oxidized to prepare supracon-conducting magnets. The wire can also be oxidized before shaping.

£ -XE E_Ê The alloy prepared in examples 1, 2 or 3 is prepared in the form of a rapidly solidified powder, rather than a ribbon, then it is compressed iso-statically hot to form a useful form , for example a ring. The shaped article is then oxidized to form a superconductive oxide or oxide-metal composite article.

AT

7 EXAMPLE 7

An oxide or oxide-metal superconductive composite is prepared as in Examples 1, 2 or 3, except that the alloy is prepared by melting, then atomization 5 of the liquid alloy using atomization in an inert gas to form a powder . The alloy powder is co-extruded with a billet of metal or metal alloy to form a composite wire, rod or tube. The coextruded product consists of a no-10 metal yau coated with the alloy. The tube can be coated on its internal or external face, or on both. The coating is then oxidized to form the oxide or oxide-metal superconducting composite. In the case of superconductive oxide-metal composites, the metal or metal alloy substrate can form a metallurgical bond between the noble metal phase of the composite, thereby promoting the adhesion of the coating.

E X EM P L E 8 20 An alloy coating is prepared by passing a wire of metal or metal alloy through a bath of the molten alloy to form the coating. The hot immersion operation is carried out under vacuum or under an inert atmosphere to avoid premature oxidation of the alloy. The coating is then oxidized to form the oxide or the oxide-metal superconducting composite as in Examples 1, 2 or 3.

EXAMPLE 9 An alloy is prepared as in Examples 1, 2 or 3, but in the form of a coating on a substrate by spray deposition, sputtering, or plasma spraying. Oxidation produces a coating of oxide or oxide-metal superconductive composite.

8 EXAMPLE_LQ.

A thin film of the alloy described in examples 1, 2 or 3 is deposited, for example by chemical vapor deposition, vacuum evaporation, cathode sputtering, epitaxy of molecular beams, mixture of ion beams or implantation of 'ions, on a metallic, insulating or semiconductor substrate. The thin film is then oxidized to form a thin film of oxide or oxide-metal superconducting composite. This technique is particularly useful in the manufacture of integrated circuits, and it can be used for example to produce Josephson junction devices.

Other embodiments are set out in the following claims.

Claims (61)

9 1. Process for the preparation of a superconductive oxide comprising stages consisting in combining the metallic elements of this 5-oxy to form an alloy; and oxidize this alloy to form this superconductive oxide. 2. The method of claim 1, wherein these metallic elements are combined in stoichiometric proportions. 3. The method of claim 1, wherein this alloy is brought into a form before this oxidation stage. 4. The method of claim 3, wherein this form comprises a wire, ribbon, sheet, rod or ring. 5. The method of claim 4, wherein this wire is wound around a metal core in the preparation of a superconductive magnet. 6. The method of claim 3, wherein this alloy is brought in this form by wire drawing, extrusion, coextrusion, hot isostatic compression or rolling. 7. The method of claim 1, wherein said alloy is provided in the form of a coating prior to this oxidation stage. 8. The method of claim 7, wherein said coating is prepared by coextrusion, hot immersion, spray deposition, sputtering or plasma spraying. 9. The method of claim 1, wherein this alloy is provided in the form of a thin film before this oxidation stage. 10. The process of claim 9, wherein said thin film is prepared by chemical vapor deposition, vacuum evaporation, sputtering, T 10 molecular beam epitaxy, mixing of ion beams or ion implantation. 11. The method of claim 1, wherein this alloy is formed by fusing these metallic elements together, then transforming them by rapid solidification. 12. The method of claim 11, wherein this rapid solidification transformation comprises spinning in the molten state or atomization in an inert gas. 13. The method of claim 1, wherein this alloy is formed by melting these metal elements together, then by casting them. 14. The method of claim 1, wherein these metallic elements are selected from the group consisting of La, Ba, Cu, Y and Sr. 15. The method of claim 1, wherein these metallic elements comprise La, Ba and Cu. 16. The method of claim 1, wherein these metallic elements comprise La, Sr and Cu. 17. The method of claim 1, wherein these metallic elements include Y, Ba and Cu. 18. The method of claim 1, wherein these metallic elements comprise Lu, Ba and Cu. 19. The method of claim 1, wherein these metallic elements comprise Lu, Sr and Cu. 20. Superconductive oxide prepared according to the process of claims 1, 3, 7 or 9. 21. A method of preparing an oxide-superconducting metal composite comprising the steps of combining the metallic elements of this oxide with a noble metal to form an alloy; and oxidizing this alloy under conditions sufficient to oxidize these metallic elements to this oxide without oxidizing this noble metal to form this composite. 1 1 22. The method of claim 21, in which this noble metal comprises a stoichiometric excess of one of these metallic elements of this oxide. 23. The method of claim 21, wherein said noble metal is Cu. 24. The method of claim 21, wherein said noble metal is Ag, Pt, Pd or Au. 25. The method of claim 21, wherein said alloy is brought into a form before this oxidation stage. 26. The method of claim 25, wherein said form comprises a wire, ribbon, sheet, rod or ring. 27. The method of claim 26, wherein said wire is wound around a metal core in the superconducting magnet preparation. 28. The method of claim 25, wherein said alloy is brought in this form by wire drawing, extrusion, coextrusion, hot isostatic pressing or rolling. 29. The method of claim 21, wherein said alloy is provided in the form of a coating before this oxidation stage. 30. The method of claim 29, wherein said coating is prepared by coextrusion, hot immersion, spray deposition, sputtering or plasma spraying. 31. The method of claim 21, wherein said alloy is provided in the form of a thin film 30 prior to this oxidation stage. 32. The method of claim 31, wherein said thin film is prepared by chemical vapor deposition, vacuum evaporation, sputtering, epitaxy of molecular beams, mixing of ion beams or ion implantation. 12 33. The method of claim 21, in which this alloy is formed by melting these metallic elements and this noble metal with each other, followed by a rapid solidification treatment. 34. The method of claim 33, wherein said rapid solidification treatment comprises melt spinning or atomization in an inert gas. 35. The method of claim 21, wherein said alloy is formed by melting these metallic elements and this noble metal together and then casting them. 36. The method of claim 21, wherein these metallic elements are chosen from the group consisting of La, Ba, Cu, Y and Sr. 37. The method of claim 21, wherein these metallic elements comprise La, Ba and Cu. 38. The method of claim 21, wherein these metallic elements comprise La, Sr and Cu. 39. The method of claim 21, wherein these metallic elements include Y, Ba and Cu. 40. The method of claim 21, wherein these metallic elements comprise Lu, Ba and Cu. 41. The method of claim 21, wherein these metallic elements comprise Lu, Sr and Cu. 42. A superconductive oxide-metal composite prepared according to the process of claims 21, 25. 29 or 31. 43. Superconductive oxide-metal composite comprising a superconductive oxide phase intimately mixed with a noble metal phase to give this composite improved mechanical properties. 44. The composite of claim 43, in which this oxide phase comprises an oxide of metallic elements chosen from the group consisting of La, Ba, Cu, Y and Sr. 45. The composite of claim 43, wherein said oxide phase comprises an oxide of La, Ba and Cu. C »13 46. The composite of claim 43, in which this oxide phase comprises an oxide of La, Sr and Cu. 47. The composite of claim 43, wherein this oxide phase comprises an oxide of Y, Ba and Cu. 48. The composite of claim 43, in which this oxide phase comprises an oxide of Lu, Ba and Cu. 49. The composite of claim 43, wherein this oxide phase comprises an oxide of Lu, Sr and Cu. 50. The composite of claim 43, wherein said noble metal phase comprises Ag, Pt, Au or Pd. 51. The composite of claim 43, in which this noble metal phase comprises a stoichiometric excess of one of the metallic elements of this oxide. 52. The composite of claim 51, wherein this noble metal phase comprises Cu. 53. The composite of claim 43, wherein said composite is in the form of a thin film. 54. The composite of claim 43, wherein said composite is in the form of a coating. 55. The composite of claim 43, wherein said composite is in the form of a shaped article. 56. The composite of claim 55, wherein said shaped article comprises a wire, ribbon, rod or ring. 57. The composite of claim 56,. In which this son is wound around a metal core to form a superconductive magnet. -58. The method of claim 1, wherein these metallic elements include europium, ba-30 ryum and copper. 59. The method of claim 21, wherein these metallic elements include europium, barium and copper. 60. The composite of claim 43, wherein said oxide phase comprises an oxide of europium, barium and copper. ► s 14 61. The method of claim 1, wherein these metallic elements include europium, barium and copper in a 1-2-3 ratio, respectively.